[FIR] Implement IMPLICIT_NOTHING_*_TYPE diagnostics

compiler/testData/diagnostics/tests/controlStructures/ifToAnyDiscriminatingUsages.fir.kt

@@ -30,13 +30,13 @@ fun testReturnFromAnonFun() =
             return <!RETURN_TYPE_MISMATCH!>if (true) 42 else println()<!>
         })
 
-fun testReturn1() =
+fun <!IMPLICIT_NOTHING_RETURN_TYPE!>testReturn1<!>() =
         run {
             return <!RETURN_TYPE_MISMATCH!>if (true) 42
                    else println()<!>
         }
 
-fun testReturn2() =
+fun <!IMPLICIT_NOTHING_RETURN_TYPE!>testReturn2<!>() =
         run {
             return <!RETURN_TYPE_MISMATCH!>if (true) 42
                    else if (true) 42

compiler/testData/diagnostics/tests/controlStructures/kt10717.fir.kt

@@ -1,10 +1,10 @@
 // !DIAGNOSTICS: -UNUSED_EXPRESSION -UNREACHABLE_CODE -UNUSED_PARAMETER -RETURN_NOT_ALLOWED
 
-fun test1() = run {
+fun <!IMPLICIT_NOTHING_RETURN_TYPE!>test1<!>() = run {
     return <!RETURN_TYPE_MISMATCH!>"OK"<!>
 }
 
-fun test2() = run {
+fun <!IMPLICIT_NOTHING_RETURN_TYPE!>test2<!>() = run {
     fun local(): String {
         return ""
     }

compiler/testData/diagnostics/tests/controlStructures/kt799.fir.kt

@@ -14,7 +14,7 @@ fun test() {
 
 val a : Nothing = <!RETURN_NOT_ALLOWED!>return<!> 1
 
-val b = <!RETURN_NOT_ALLOWED!>return<!> 1
+val <!IMPLICIT_NOTHING_PROPERTY_TYPE!>b<!> = <!RETURN_NOT_ALLOWED!>return<!> 1
 
 val c = doSmth(if (true) 3 else <!RETURN_NOT_ALLOWED!>return<!>)
 

compiler/testData/diagnostics/tests/controlStructures/whenToAnyDiscriminatingUsages.fir.kt

@@ -24,7 +24,7 @@ fun testResultOfLambda2() =
             }
         }
 
-fun testReturn1() =
+fun <!IMPLICIT_NOTHING_RETURN_TYPE!>testReturn1<!>() =
         run {
             return <!RETURN_TYPE_MISMATCH!>when {
                 true -> 42
@@ -32,7 +32,7 @@ fun testReturn1() =
             }<!>
         }
 
-fun testReturn2() =
+fun <!IMPLICIT_NOTHING_RETURN_TYPE!>testReturn2<!>() =
         run {
             return <!RETURN_TYPE_MISMATCH!>when {
                 true -> 42
@@ -80,4 +80,4 @@ val testUsage5: Any get() =
         when {
             true -> 42
             else -> println()
-        }
+        }